Method and device for enhancing transdermal agent flux

Abstract

A substantially conical shaped microprojection having a wall defining an interior region, said microprojection wall including a plurality of openings; and a biocompatible coating disposed on the interior region of the microprojection. In a preferred embodiment, the microprojection is formed by deforming a region of a substantially planar sheet.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 490,739, filed Aug. 4, 2003. Related applications include U.S. application Ser. No. ______, attorney docket number ALZ5037USANP, filed Aug. 3, 2004, and U.S. application Ser. No. ______, attorney docket number ALZ5037USANP2, filed Aug. 3, 2004.FIELD OF THE PRESENT INVENTION [0002] The present invention relates generally to devices for transdermal delivery and sampling of agents. More particularly, this invention relates to the transdermal delivery of agents through a body surface, as well as the transdermal sampling of agents from a body surface, such as glucose, other body analytes and substances of abuse, such as alcohol and illicit drugs. BACKGROUND OF THE INVENTION [0003] Interest in the transdermal delivery of beneficial agents, especially such agents as high molecular weight peptides, proteins and oligonucleotides and vaccines, to the human body by delivery...

AI Technical Summary

Benefits of technology

[0020] The present invention substantially reduces or overcomes the limitations of prior art coated microprojection systems by transdermally delivering a biologically active agent using a microprojection array having a plurality of microprojections, at least one of the microprojections having an interior region that is coated with a solid, substantially dry coating containing at least one biologically active agent, wherein the microprojections can be inserted into and through the tissue (or stratum corneum) without substantially exposing the coating to physical contact with the tissue. The biologically active agent is selected to be sufficiently potent to be effective when delivered from a solid coating on a plurality of skin piercing microprojections. The coating preferably has sufficient water solubility such that when the microprojections are disposed within the patient's tissue the coating is easily and quickly dissolved, thereby releasing the biologically active agent.

Problems solved by technology

Transdermal delivery of the noted agents still face significant problems.

For example, in many instances, the rate of delivery or flux of such agents through the skin is insufficient to produce a desired therapeutic effect due to their large size / molecular weight and / or inability to pass through natural pathways (pores, hair follicles, etc.) that exist in the skin.

Likewise, the passive flux of small (e.g., 200 to 500 daltons) water soluble agent molecules is often limited.

Unfortunately, because of the extremely small size of the microprojections, the formation of barbs and similar anchoring elements on the microprojections is technically challenging and adds to the cost.

One drawback of coated microprojection systems is however the risk of physically displacing the coating from the microprojections during insertion of the microprojections into and through the skin (i.e., stratum corneum).

This could result in a substantial amount of the agent not being deposited far enough into the tissue where it would be in contact with interstitial fluids.

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